1. Field of the Invention
This invention relates to a recording and reproducing apparatus which can record and reproduce two kinds of video signals having different aspect ratios.
2. Description of the Related Art
Conventionally, television sets normally have an aspect ratio of 4:3 as seen from FIG. 9(a). Accordingly, video apparatus which are connected in use to a television set, such as, for example, video tape recorders, are produced so as to match the aspect ratio.
On the other hand, high definition television sets which have been developed recently include a number of scanning lines equal to twice that of conventional television sets and have a different aspect ratio of 16:9 as seen from FIG. 9(b). Accordingly, a video image which is high in picture quality and provides the feeling of presence can be obtained on a high definition television set. However, since high definition television sets are considerably expensive in the present condition, television sets having the same number of scanning lines of 525 as that of conventional television sets but having the different aspect ratio of 16:9 are produced.
Consequently, also video tape recorders are required to treat a video signal wherein the number of scanning lines is 525 and the aspect ratio is 16:9. However, since television sets having the aspect ratio of 4:3 prevail in the present condition, video tape recorders which can record and reproduce both of a video signal having the aspect ratio of 4:3 and another video signal having the aspect ratio of 16:9 are produced.
In a video tape recorder of the type just described, aspect ratio information for the distinction between the aspect ratios of 4:3 and 16:9 is recorded in a superimposed condition at a control portion or a vertical blanking portion of a video signal.
A video tape recorder which can record and reproduce two different video signals having the different aspect ratios in this manner is normally constructed such that video signals having the different aspect ratios are processed in the same transmission band.
In a video tape recorder of the type described above, when a video signal having the aspect ratio of 4:3 as seen in FIG. 9(a) is to be recorded, a predetermined overshoot is added in order to emphasize a contour of an image as seen from FIG. 10(a).
On the other hand, when another video signal having the aspect ratio of 16:9 as seen in FIG. 9(b) is to be recorded, since it is recorded in the same transmission band as a video signal having the aspect ratio of 4:3 as described above, the video signal is reduced in the horizontal direction as seen from FIG. 10(b) and an overshoot similar to that which is added to a video signal having the aspect ratio of 4:3 is added to the video signal.
As seen in FIG. 11(a), the width A of an overshoot when a video signal having the aspect ratio of 4:3 is reflected on a television set is set to a value at which the picture quality is not deteriorated. However, if a video signal having the aspect ratio of 16:9 is reflected in this condition on the television set as seen in FIG. 11(b), the image is expanded in the horizontal direction, and also the width B of the overshoot is expanded in the horizontal direction. Consequently, the picture quality is deteriorated.
A similar phenomenon occurs not only in overshoot but also in any other factor of the picture quality such as a ringing or a noise component.